September, season of mists and mellow fruitfulness on the one hand, and season of frenetic, expensive, back-to-schoolness on the other. All over the country, children have returned to school in oversized uniforms and briefly smart shoes, to prepare for a new year. Parents have sworn to themselves that this year, the school lunches will be imaginative, and they will put to good use the start of the school year to begin an evening class, get fit, or initiate some other plan they've been long fingering - because they're really not that into it. September, as much as January, punctuates our year as a beginning and stirs the subconscious into planning, well, stuff.

The rhythm of life is a powerful thing and our brain and our moods are hard-wired to it. So, in the same way on a Sunday evening, I feel slightly depressed at having to do my homework - until I remember I'm 43. (And the theme from Glenroe pushes me over the edge altogether.) September pushes some button, long drilled into me by 23 academic years of full-time education, that says, "It's September, the summer's over - so stop faffing about and knuckle down to work." The fact that I now work 12 months of the year, rather than the academic eight, and haven't faffed half as much as I'd like to, has no bearing on this.

September, and the start of the school year, remains a natural time for undertaking new challenges - for adults as well as kids - which may, depending on where your head is at, excite or dismay you. But the urge to get up and go is there none the less.

For many years I thought I would use September and the following months to write my novel and walk dreamily through the romantically wet leaves thinking up clever plots. Until this year, sadly, when I finally realised I hate drizzle - and walking. And that my novel, alas, has probably stagnated fatally, as it's fallen to a very poor sixth, behind the kids, work, the house, work and laziness.

This September, I'm considering yoga or Pilates as my new autumnal project. Although with some pre-conditions: the class would have to be very convenient, as I'm pretty lukewarm on heading out on cold, dark evenings; and it can't be remotely boring or embarrassing - as how could I, or indeed anyone, be expected to keep it up if it was. There's commitment for you.

I've a junior elephant (infant) and a first year, to add into the usual back-to-school mix this year. Which does add a certain frisson of stress to the whole thing, as they feign pre-school nerves in order to manipulate me into comforting them with retail therapy. But what really strikes me this year - as my last child enters the national school system - is that I've been following this annual cycle for pretty much my whole life and as much as there's a time to reap and a time to sow, there's a time to get stuck in to something. And I think September is it.

So take advantage of your natural hard-wiring and think about your life and what you might like to get out of the long winter evenings ahead. Have you always wanted to learn to French polish? Or could you be the next big star of your local Am Dram society? It doesn't really matter what it is - the thing to do, is to do it. It's good for you. And if there is a time for every purpose under heaven - there's no time like the present.